Chapter 9 - Alcohol Flashcards
What is the only alcohol fit for human consumption?
ethyl alcohol (ethanol)
Both ____ and ____ are commonly encountered but are completely unsafe to drink
isopropyl and methyl alcohol (or methanol)
percentage of alcohol (or alcohol by volume) refers to…
the amount of alcohol in grams per 100 ml of solution
-proof of alcohol is twice the number of the percentage
how much is one standard drink?
14 grams of 100% alcohol
-1.5oz of 50% alcohol
-5oz of wine
-12oz of beer
alcohol is produced by ____, which is ____
fermentation; the product of yeast consuming starches and sugars in grains or fruits
-upper limit of % produced is about 15%
-wine 12-15%, beer 5%
What is distillation?
process that increases the percentage of alcohol in a solution by heating then condensing vapour
-used to make drinks with much higher alc concentrations (rum, vodka, etc)
History of alcohol
fermented since at least 6000 BC (mentions of wine in the bible); used by Greeks for medicine and recreation; pubs appeared in England by the 12th century
pharmacokinetics of alcohol
ethanol is water and lipid soluble so it is easily absorbed; enters via GI tract; quicker absorption on an empty stomach and thru carbonated drinks
Alcohol impairs which transporter in the upper GI?
thiamine (B1); can create deficiencies on body and brain
What is Blood-Alcohol Concentration (BAC)?
grams of alcohol per 100ml of blood; BAC = 0.04 is produced by about two drinks; max BAC occurs after 45mins; used for legal definitions of intoxication
metabolizing alcohol
occurs in stomach and liver; converted by alcohol dehydrogenase; some is metabolized by the P450 enzyme (CYP2E1)
alcohol dehydrogenase 1C*1 allele polymorphism
increased alcohol dehydrogenase; alcohol converted to acetaldehyde more quickly; greater accumulation of acetaldehyde
acetaldehyde H2*2 allele polymorphism
less aldehyde dehydrogenase; slower breakdown of acetaldehyde; greater accumulation of acetaldehyde (e.g., flushing of face)
-~1/2 of people of Asian descent
elimination of alcohol follows ____
zero order kinetics; on average about 7g of alcohol per half hour (half a standard drink)
breathalyzer tests use what to determine BAC?
Ratio of alcohol concentration in expelled air to blood is 1:2,300
- 0.11 breathalyzer = 0.11 BAC
alcohol and GABAA receptors
positive modulator for ionotropic GABAA receptors; Cl- ions enter the neuron, hyperpolarize the cell, which inhibits neural activity; Increases the length of receptor activation and increases the flow of Cl- into the neuron
depressant effects of alcohol are due to the receptors in ____
Cerebral cortex, hippocampus, and thalamus
–responsible for the depressant effects on
cognition/memory
rewarding effects of alcohol are due to the receptors in ____
Nucleus accumbens and ventral tegmental area
– responsible for increased dopamine associated with reward
alcohol and reward pathway
- Alcohol facilitates GABAA receptors on GABA neurons in NA (that project to VTA) – leading to release of DA (disinhibition)
- Alcohol activates GABAA receptors located on GABA neurons in the VTA which normally inhibit DA release (disinhibition)
- Alcohol indirectly inhibits GABA neurons by increasing levels of β-endorphin
chronic use of alcohol leads to…
- Reduced number of GABAA receptors
2.Reduced response of GABAA receptors to alcohol
3.Less release of β-endorphin, resulting in less inhibition of GABA neurons
alcohol and glutamate receptors
Alcohol inhibits NMDA glutamate receptors (binds to inside of ion channel, non-competitive antagonist); chronic administration leads to increased number of NMDA receptors
-during withdrawal: increased NMDA receptors = more excitation (by glutamate) coupled with lower GABAA receptor levels; increases risk of seizures
alcohol and calcium
Alcohol inhibits L-type calcium channels: important for calcium influx at nerve terminals and NT release; suppresses release of vasopressin (ADH) in hypothalamus (alcohol leads to increased urination)
alcohol and other NTs - serotonin
increases serotonin levels in the nucleus
accumbens by interacting with the ionotropic 5-HT3 and metabotropic 5-HT2A receptors.
– Note: Blocking these 5-HT receptors in NA, blocks rewarding effects of alcohol
alcohol and other NTs - endocannabinoid system
May be part of reward circuit for alcohol.
– Similar to 5-HT, blocking cannabinoid
receptors in NA blocks release of DA in response to alcohol
pharmacological effects
generally a depressant on behaviour and cognitive functioning; mood changes (euphoria, reduced anxieties, reduced inhibitions); ballance/equillibrium effected at low dose
alcohol priming
refers to the tendency for individuals to
feel an urge to drink more alcohol after having one of two drinks
tension reduction hypothesis
suggests that habitual users of alcohol use it to reduce stress
2 possible effects of alcohol
- Alcohol stupor (or drunken stupor) can occur at BACs of 0.20 or higher.
- Reversible drug-induced dementia occurs at BACs of 0.25 and higher and is associated with blackout (blackouts involve complete lack of memory for a period of alcohol intoxication)
-at higher BACs, individuals tend to become unconscious
-BACs of 0.25 or higher can cause alcohol poisoning
4 dangers of chronic consumption
- alcoholic cardiomyopathy
- cirrhosis (liver)
- fetal alcohol syndrome
- Wernicke-Korsakoff’s syndrome
what is fetal alcohol syndrome
facial and developmental abnormalities associated with mother’s alcohol use during
pregnancy (peak BAC and duration of
alcohol exposure)
-prevalence: 0.2–1.5 per 1,000 births
-increased risk of spontaneous abortion
Acute tolerance
refers to tolerance that onsets during a
given drug taking session
Metabolic tolerance
involves an increase in liver
enzymes that metabolize alcohol
Pharmacodynamic tolerance
occurs as NMDA receptors are upregulated to offset the inhibitory effects of alcohol
Behavioural tolerance
refers to reduced
behavioral impairment observed in experienced drinkers
Type I Alcohol Addiction
typically occurs in older individuals who are at high psychosocial risk for addiction
Type II Alcohol Addiction
typically occurs in younger individuals who are at a high genetic risk for addiction
Abstinence syndrome
medically more severe and more deadly than opioid withdrawal; if untreated, mortality can be as high as 1 in 7; detoxification should be carried out in an inpatient medical setting
4 stages of alcohol withdrawal
Stage 1: tremors, rapid heartbeat, hypertension, heavy sweating, loss of appetite, insomnia
Stage 2: hallucinations (auditory, visual, and/or tactile)
Stage 3: delusions, disorientation, delirium
Stage 4: seizures
Cognitive Behavioural Therapy (treating alcohol addiction)
aim to improve cognitive and behavioral skills to change problematic patterns of alcohol use
Pharmacotherapy (treating alcohol addiction)
Disulfiram (Antabuse): used to make drinking less likely by creating aversive effects following alcohol consumption.
Naltrexone: opioid antagonist that may block
reinforcing properties of alcohol.
Acamprosate (Campral): FDA approved for the
treatment of alcohol addiction; thought to reduce cravings for alcohol by affecting calcium channels to reduce activity of NMDA receptors
